2020 Day 2 Complete

2020/day02/main.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()
+	validate(inp, h.OptArgNumber(1, "1"))
+}
+
+func validate(input []string, p string) {
+	policy := h.Atoi(p)
+	var good, bad []string
+	for _, v := range input {
+		if policy == 1 {
+			if validSledRentalPolicy(v) {
+				good = append(good, v)
+			} else {
+				bad = append(bad, v)
+			}
+		} else {
+			if validTobogganPolicy(v) {
+				good = append(good, v)
+			} else {
+				bad = append(bad, v)
+			}
+		}
+	}
+	fmt.Printf("There are %d valid passwords\n", len(good))
+}
+
+func validSledRentalPolicy(line string) bool {
+	min := -1
+	max := -1
+	req := ""
+	var buff string
+	for i := 0; i < len(line); i++ {
+		if req != "" {
+			buff = buff + string(line[i])
+			continue
+		}
+		switch line[i] {
+		case '-':
+			min = h.Atoi(buff)
+			buff = ""
+		case ' ':
+			if max == -1 {
+				max = h.Atoi(buff)
+				buff = ""
+			}
+		case ':':
+			req = buff
+			buff = ""
+		default:
+			buff = buff + string(line[i])
+		}
+	}
+	reqCount := strings.Count(buff, req)
+	return reqCount >= min && reqCount <= max
+}
+
+func validTobogganPolicy(line string) bool {
+	idx1 := -1
+	idx2 := -1
+	req := byte(' ')
+	var buff string
+	for i := 0; i < len(line); i++ {
+		if req != ' ' && line[i] != ' ' {
+			buff = buff + string(line[i])
+			continue
+		}
+		switch line[i] {
+		case '-':
+			idx1 = h.Atoi(buff)
+			buff = ""
+		case ' ':
+			if idx2 == -1 {
+				idx2 = h.Atoi(buff)
+				buff = ""
+			}
+		case ':':
+			req = line[i-1]
+			buff = ""
+		default:
+			buff = buff + string(line[i])
+		}
+	}
+	match1, match2 := buff[idx1-1] == req, buff[idx2-1] == req
+	return match1 != match2
+}

2020/day02/testinput

@@ -0,0 +1,3 @@
+1-3 a: abcde
+1-3 b: cdefg
+2-9 c: ccccccccc

helpers/helpers.go

@@ -76,6 +76,13 @@ func GetArgNumber(i int) string {
 	return ""
 }
 
+func OptArgNumber(i int, def string) string {
+	if len(os.Args) > i {
+		return os.Args[i]
+	}
+	return def
+}
+
 func StdinToIntSlice() []int {
 	var ret []int
 	st := StdinToStringSlice()